An air intake silencer assembly (10) at the intake of an air handling system includes a plenum housing (20) having an inlet (23) end for receiving air and having an outlet port (24) for discharging air. Two baffle panels (28) in spaced relation in the housing define, with the housing, an inlet chamber (30) , a central chamber (32), and a discharge chamber (34) . A plurality of tubular (36) members is supported by the baffle panels (28) and each includes a perforated core (40) and a sound dissipating fiber wrapping (42) . Air flows into the inlet chamber, through the plurality of tubular members to the discharge chamber, and is discharged from the discharge chamber through the outlet port.

What is claimed is: An air intake silencer assembly at the intake of an air handling system comprising, a plenum housing having an inlet end for receiving air and having an outlet port for discharging air, at least two baffle panels in spaced relation in the housing and defining, with the housing, an inlet chamber, a central chamber, and a discharge chamber, a plurality of tubular members supported by the baffle panels and each including a perforated core and a sound dissipating fiber wrapping, and wherein air flows into the inlet chamber, through the plurality of tubular members to the discharge chamber, and is discharged from the discharge chamber through the outlet port.

2.

The air intake silencer assembly of claim 1 , wherein the core is stainless steel.

3.

The air intake silencer assembly of claim 1 , wherein the fiber wrapping is cotton.

4.

The air intake silencer assembly of claim 1 , wherein the tubular member is a water filtration device.

5.

The air intake silencer assembly of claim 1 , wherein the housing is generally box shaped.

6.

The air intake silencer assembly of claim 1 , wherein the baffle panels are identical.

7.

The air intake silencer assembly of claim 1 , wherein the baffle panels and the tubular members comprise a removable subassembly.

8.

The air intake silencer assembly of claim 1 , wherein the area of the perforations on the outer surface of the core is approximately 30% of the outer surface of an identical core without perforations.

9.

The air intake silencer assembly of claim 1 , further including an outwardly extending flange at the inlet end, wherein the flange is used to secure the device to an air intake filter.

10.

The air intake silencer assembly of claim 9, wherein a pipe connects the outlet port and an air handling system.

11.

The air intake silencer assembly of claim 1 , wherein the tubular members are all generally parallel to each other.

12.

An air intake silencer assembly at the intake of an air handling system, the air intake silencer assembly comprising, a plenum housing including an inlet end for receiving filtered air, at least two baffle panels in spaced relation in the housing and with the housing defining an inlet chamber, a central chamber, and a discharge chamber, and a plurality of tubular members substantially located within the central chamber, each tubular member including ends supported by the baffle panels and including a perforated stainless steel core and a sound dissipating fiber wrapping, wherein the filtered air flows into the inlet chamber, undergoes reflection and pressure equalizing in the inlet chamber, flows from the inlet chamber through the plurality of tubular members to the discharge chamber, undergoes reflections and pressure equalizing in the discharge chamber, and is discharged from the discharge chamber through an outlet port of the housing.

13.

The air intake silencer assembly of claim 12, wherein the tubular member is a water filtration device. W 2 .

14.

The air intake silencer assembly of claim 12, wherein the housing is generally box shaped.

15.

The air intake silencer assembly of claim 12, wherein there are two identical baffle panels.

16.

The air intake silencer assembly of claim 12, wherein the baffle panels and the tubular members comprise a removable subassembly.

17.

The air intake silencer assembly of claim 12, wherein the area of the perforations on the outer surface of the core is approximately 30% of the outer surface of an identical core without perforations.

18.

The air intake silencer assembly of claim 12, further including an outwardly extending flange at the end with the inlet port, wherein the flange is used to secure the device to an air intake filter.

19.

The air intake silencer assembly of claim 18, wherein a pipe connects the outlet port and an air compressor.

20.

The air intake silencer assembly of claim 12, wherein the tubular members are all generally parallel to each other.

The present invention relates to an air intake silencer assembly for attenuating noise of air flowing into an air handling system, such as an air compressor or blower.

Background of the Invention

Air handling systems, such as air compressors or blowers, involve the intake of air from an interfacing environment. The moving air, as it reaches the intake of the air handling system, is subject to pressure variations due to the interaction of the air with stationary and moving objects. These pressure variations in the air manifest as sound, with annoying or unwanted sound broadly defined as noise. Sound propagates through air, other gases and surrounding media at a certain velocity and in the form of pressure waves from a source to a receiver. Most sound at the air intake of an air compressor is the result of complex interactions between the air and obstacles in its path, and is composed of a number of frequencies.

Prior art attempts at noise attenuation at the intake of industrial air compressors have included the use of an acoustically lined duct. Due to the tendency of the acoustic material in the duct to break off, such an acoustically lined duct has typically been located before an air intake filter. The air intake filter thus prevents any broken off portions of this material from reaching the compressor. One shortcoming in this approach is the significant resultant distance between the lined duct and the air compressor, which promotes the escaping of noise through the connecting pipes and hoses. As the noise escapes from its source, its suppressions become significantly more difficult to accomplish by effective and economical means. Other means to suppress or prevent the further propagation of the noise into the surrounding environment include barriers such as free-standing walls and enclosing structures.

Barriers are characterized by high transmission loss and highly absorptive surfaces, and they are effective in reducing high frequency short wavelength noise. In general, the physical size of sound barriers should be approximately at least three times larger than the wavelength of the frequency of the major noise contributors. In the case of relatively low frequency and long wavelength noise components, sound barriers could thus be significant in size and cost. When a significant reduction of the noise escaping from the intake of an air compressor is required, then an acoustical enclosure can be used. Typically, acoustical enclosures are constructed with relatively high transmission loss and absorptive internal panels and can be placed directly over the source of the noise. Acoustical enclosures, for the same reasons mentioned with respect to acoustical barriers, may also be large in size and expensive. Acoustical enclosures, which should be air tight to reduce the amount of the internal noise radiating to the outside, may also cause heat retention issues which further complicate their design and increase their cost because of the necessity for cooling and special venting systems.

Summary of the Invention

In one embodiment, the invention provides an improved and cost effective air intake silencer assembly which acts as a noise attenuating device and which can be positioned immediately downstream of an air intake filter and directly connected to the intake of an air handling system. Additionally, the silencer assembly provides minimal resistance to the air flow passing therethrough thus providing the downstream air handling system the appropriate capacity necessary for its rated performance. Further, the material in the silencer assembly remains in position and does not break free under the pressure and shearing actions of the air flow.

One embodiment of an air intake silencer assembly at the intake of an air handling system includes a plenum housing including an inlet end for receiving filtered air, at least two baffle panels in spaced relation in the housing and with the housing defining an inlet chamber, a central chamber, and a discharge chamber, and a plurality of tubular members substantially located within the central chamber. Each tubular member includes ends supported by the baffle panels and includes a perforated core and a sound dissipating fiber wrapping. Filtered air flows into the inlet chamber,

undergoes reflection and pressure equalizing in the inlet chamber, flows from the inlet chamber through the plurality of tubular members to the discharge chamber, undergoes reflections and pressure equalizing in the discharge chamber, and is discharged from the discharge chamber through an outlet port of the housing.

Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.

Brief Description of the Drawings

Fig. 1 is one embodiment of an air intake silencer assembly in an air compression system wherein the silencer assembly is mounted downstream of an air intake filter and upstream of an air compressor;

Fig. 2 is a perspective view of one embodiment of an air intake silencer assembly;

Fig. 3 is a cross sectional view of the air intake silencer assembly of Fig. 2;

Fig. 4 illustrates a removable assembly of the air intake silencer assembly of Fig. 2;

Fig. 5(a) and (b) are perspective views of a perforated tubular member wrapped with fiber; and

Fig. 6 illustrates a baffle panel.

Detailed Description of the Preferred Embodiments

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The order of limitations specified in any

method claims does not imply that the steps or acts set forth therein must be performed in that order, unless an order is explicitly set forth in the specification.

Fig. 1 illustrates a preferred placement of an air intake silencer assembly 10 in an air handling system, such as an air compression system 12. In particular, the air intake silencer assembly 10 is mounted downstream of an air intake filter 14 and upstream of an air compressor 18. Air flows into the air intake filter 14 where it is filtered, through the air intake silencer assembly 10, to a pipe 16, and then to the air compressor 18, where the air is compressed in one or more stages and then delivered to a compressed air utilization system (not shown).

With reference to Figs. 2 and 3, the air intake silencer assembly 10 includes a plenum housing 20 receiving filtered air at an inlet end 22. A flange 21 at end 22 allows easy mounting of the silencer assembly 10 to the air intake filter 14. Further, brackets 19 can be used to mount the assembly 10 to a cabinet or housing (not shown) of the air compression system 12, such as a housing for electronic control components of the system 12. The air flows through the silencer assembly 10 to an outlet port 24 that is connectable to pipe 16. In a preferred embodiment, the outlet port 24 is located on a side 26 of the housing 20 rather than an end of the housing opposite end 22. The air intake silencer assembly 10 can be placed downstream of the air intake filter 14 because, as described below, the air intake silencer assembly 10 preferably includes material that doesn't break off and flow into the downstream air handling system.

In particular, with reference to Figs. 3, 4, and 6, in one embodiment, the air intake silencer assembly 10 includes two baffle panels 28 spaced apart from each other in the housing 20 to define, with the housing 20, an inlet chamber 30, a central chamber 32, and a discharge chamber 34. Preferably, the baffle panels 28 are arranged parallel to each other in the housing 20. In other embodiments, it is contemplated that additional baffle panels be used to define more than a single central chamber. Tubular members 36 for dissipating sound are supported by the baffle panels 28 such that each tubular member 36 is substantially located within the central chamber 32. Specifically, the baffle panels 28 include apertures 29 through which the ends of the tubular members can be inserted and supported. The tubular members 36, together with the baffle

panels 28, form a subassembly 38 as shown in Fig. 4, which is easily insertable in and removable from the housing 20.

As shown in Figs. 5(a)-(b), each tubular member 36 includes a perforated core 40 with sound dissipating fiber 42 wrapped around the core 40. The tubular member in one embodiment is a water filtration device, such as available from Johnson Filtration Products, Inc. The perforated core 40 can be stainless steel. Further, in one embodiment, the area of the perforations on the outer surface of the core is approximately 30% of the outer surface of an identical core without perforations. The core can be made of other materials such as a fine wire mesh. Further, in one embodiment, the fiber is cotton string, although in other embodiments, the fiber can be one or more other fibers such as fiberglass yarn, nylon or polyester. Preferably, the sound dissipating fiber will not break off and will not flow into the downstream compression system 12.

In the illustrated embodiment, the inlet chamber 30 and the discharge chamber 34 act as reactive plenums. Filtered air flows from the air intake filter 14 to the inlet chamber 30. Air in the inlet chamber 30 undergoes reflections such that pressure variations are somewhat equalized in this inlet chamber. Air then flows from the inlet chamber 30 through each of the plurality of tubular members 36 to the discharge chamber 34. Sound in the central chamber 32 is attenuated due to the sound dissipating effects of the fiber 42. Air in the discharge chamber 34 undergoes reflections such that pressure variations are somewhat equalized in the discharge chamber. Air is discharged from the discharge chamber 34 through the outlet port 24.

In other embodiments, the inlet chamber 30 and/or the discharge chamber 34 can also be lined with absorptive (dissipating) material such that sound is also dissipated in these chambers.

Various features and advantages of the invention are set forth in the following claims.